Baxi 105e gets stuck in DHW mode

[Mushy]

Hi,

I have a problem with my Baxi 105e Combi in that the needle from the DHW pressure differential can get stuck in the DHW mode and eventually returns several hours later. Because of this the CH does not come on until the needle retracts.

I often take the microswitch housing off and push the needle in manually. The boiler behaves fine for a while, but if the hot water tap is on for a while, say for bath or shower, then the needle again gets stuck.

Could this be a problem with debris in the venturi pipes that come from the diaphragm housing? I've tried dissembling , checking diaphragm and lubricating (WD40 is this suitable?) but no result.

CH is fine otherwise.

Can anyone suggest any possible causes?

Cheers.

 

[namsag]

Strip it out again as in take top off diaphragm housing clean the pin with fine wire wool and use silicone grease not wd40 . Take gland nut off as well and put silicone grease in there too.

 

[Mushy]

Thanks Namsag for your speedy response.

Just one thing to clear up for me if you don't mind. I don't put the grease in the actual ends of the pipes? Just round the pin and round nut thread? Sorry for not understanding.

 

[namsag]

No definitely dont put it in the pipes.
Smear the pin in it and with the gland nut removed from front of diaphragm housing just fill where the pin comes through and replace the gland nut excess will squeeze out so just wipe away

 

[Mushy]

Thanks Namsag, much appreciated.

 

[Mushy]

Greased diaphram, pins and glands. All working like a dream. Thanks very much for your help Namsag